This invention relates to an electric vehicle,and in particular to an overhead-powered self-propelled vehicle actuated by an electric motor.
The vehicle described hereinafter is intend to form part of overhead transport systems such as those used in industrial establishment for manufacture of vehicles, machines and apparatus of various kinds, where successive motion of parts, components and sub-assemblies is required in given circuits belonging to assembly lines, machining or assembly stations or the like.
there are various known kinds of self-propelled vehicles, usually with a driving wheel associated with a propelling motor and travelling along a rail or track,an auxiliary wheel being provided for making contact with a guide section member, so that when the two wheels touch and are in contact, the vehicle moves in a guided manner on and along the track.
An example of the aforementioned device is described in European patent Noumber 0 384 223.
However, the aforementioned system and other similar systems have the disadvantage that continual touching and contact between the two wheels (the driving wheel and the guide wheel) result in wear on the material forming the surface of the wheels, which leads to irregularities in the motion of the vehicle and necessitates a periodic change of wheels in order to remedy these defects. This increases the cost of maintenance of the transport installation.